WO2023219133A1

WO2023219133A1 - Finless heat exchanger, and cooling system employing same

Info

Publication number: WO2023219133A1
Application number: PCT/JP2023/017752
Authority: WO
Inventors: 大地山▲崎▼
Original assignee: 株式会社Afrex
Priority date: 2022-05-13
Filing date: 2023-05-11
Publication date: 2023-11-16

Abstract

Provided is a finless heat exchanger having side plates to which a refrigerant tube is mechanically affixed. The finless heat exchanger comprises a refrigerant tube 20 which extends in a meandering manner and which includes bent tube portions 21 curved in a U-shape, and straight tube portions 31 connected to both ends of the bent tube portions, and side plates 40 including elongated holes 41, wherein: each bent tube portion includes bent tube end portions 23 positioned on the straight tube portion sides of the bent tube portion, a main deformed portion 27 curved in an arc shape, and secondary deformed portions 25 positioned between the bent tube end portions and the main deformed portion; the main deformed portion includes a flat portion 28 formed by pressing; the secondary deformed portions have a curved shape that is secondarily deformed through the formation of the flat portion; the elongated holes have a central opening 47 for accepting the main deformed portions, and a pair of end openings 43 positioned at both ends of the central opening 47, for partially accepting the secondary deformed portions and the bent tube end portions; and the refrigerant tube is affixed to the side plates by diametrically expanding the bent tube portions with the bent tube portions inserted into the elongated holes, to cause the bent tube portions to come into close contact with the elongated holes.

Description

Finless heat exchanger and cooling system using it

The present invention relates to a finless heat exchanger and a cooling system using the same.

In the field of industrial equipment, finless heat exchangers are used as evaporators and condensers, for example in coolers for control panels and oil coolers. Finless heat exchangers do not have plate fins, so they have features such as high dust resistance, no need for maintenance, and less chance of air passage blockage due to frost.

For example, Patent Document 1 discloses a finless heat exchanger in which the ends of the heat exchanger tubes are inserted into the header through insertion holes formed in the header, and the heat exchanger tubes and the header are closely abutted by brazing. .

Further, Patent Document 2 discloses a fin-tube heat exchanger in which at least side plates or plate fins are arranged and fixed on a curved pipe part of a refrigerant tube, and plate fins are arranged and fixed on a straight pipe part of a refrigerant tube.

Patent No. 6821057 Japanese Patent Application Publication No. 2011-21799

As in Patent Document 1, when heat transfer tubes and headers are metallurgically brought into close contact by heating the brazing material, expensive large-scale heat treatment equipment is required, running costs are high, and it is not suitable for small-lot production. There are issues such as being

In the case of Patent Document 2, in order to fix the plate fins to the straight pipe portion of the refrigerant tube, it is necessary to apply high pressure to the refrigerant tube on the verge of rupture to expand the diameter, so failure of the refrigerant tube to burst occurs. There is a problem in that the yield rate decreases. Furthermore, when the material of the refrigerant tube is made of an aluminum alloy, there is also the problem that the yield rate further decreases.

Therefore, an object of the present invention is to provide a finless heat exchanger in which a refrigerant tube is mechanically fixed to a side plate.

In order to solve the above problems, a finless heat exchanger according to one aspect of the present invention includes:
A refrigerant tube extending in a meandering manner and having a U-shaped curved tube portion and a straight tube portion connected to both ends of the curved tube portion;
Equipped with a side plate having long holes,
The bent pipe portion includes a bent pipe end portion located on the side of the straight pipe portion, a main deformation portion curved in an arc shape, and a secondary deformation portion located between the bent pipe end portion and the main deformation portion. has
The main deformation part has a flat part formed by pressing,
The secondary deformation portion has a curved shape secondary to deformation due to the formation of the flat portion,
The elongated hole has a central opening that receives the main deformation part, and a pair of end openings that are located at both ends of the central opening and partially receive the secondary deformation part and the bent pipe end,
The refrigerant tube is fixed to the side plate by expanding the diameter of the curved tube portion with the curved tube portion inserted into the long hole and bringing the curved tube portion into close contact with the long hole. It is characterized by

According to this invention, the refrigerant tube can be mechanically fixed to the side plate by closely contacting the long hole and bulging out of the bent tube, thereby reducing costs and improving yield. realizable.

1 is a schematic diagram showing the configuration of a cooling system using a finless heat exchanger according to the present invention. FIG. 1 is a perspective view of a finless heat exchanger according to a first embodiment. 3 is a side view of a side plate of the finless heat exchanger shown in FIG. 2. FIG. 3 is a schematic front view of the finless heat exchanger shown in FIG. 2. FIG. FIG. 5 is a schematic front view of the finless heat exchanger shown in FIG. 4 before diameter expansion treatment. 6 is a side view of a refrigerant tube of the finless heat exchanger shown in FIG. 5. FIG. (A) is a three-dimensional diagram, and (B) is a diagram diagram. 4 is an enlarged view of long holes in the side plate of the finless heat exchanger shown in FIG. 3. FIG. 6 is an enlarged view of essential parts of the finless heat exchanger shown in FIG. 5. FIG. (A) is a perspective view of a bent pipe portion of a press-processed refrigerant tube, and (B) is a perspective view showing a state in which the bent pipe portion shown in (A) is inserted into a long hole in a side plate. . It is a figure which shows the size relationship between the curved pipe part of a press-processed refrigerant tube, and the long hole of a side plate. (A) shows the long hole on the left side and the pressed bent pipe part of the refrigerant tube on the right side, and (B) shows the state in which the bent pipe part shown in (A) is inserted into the long hole on the side plate. shows. It is an enlarged view of the long hole in the side plate of the finless heat exchanger based on 2nd Embodiment. It is an enlarged view of the long hole in the side plate of the finless heat exchanger based on 3rd Embodiment. It is an enlarged view of the long hole in the side plate of the finless heat exchanger based on 4th Embodiment. It is an enlarged view of the long hole in the side plate of the finless heat exchanger based on 5th Embodiment. It is an enlarged view of the long hole in the side plate of the finless heat exchanger based on 6th Embodiment.

Hereinafter, embodiments of a cooling system 1 according to the present invention will be described with reference to the drawings. In the following explanation, terms indicating specific directions or positions (for example, terms including "top", "bottom", "right", "left", "front", and "back") will be used as necessary. However, the use of these terms is to facilitate understanding of the present disclosure with reference to the drawings, and the technical scope of the present disclosure is not limited by the meanings of these terms. Further, the following description is essentially only an example, and is not intended to limit the present disclosure, its applications, or its uses. Furthermore, the drawings are schematic, and the proportions of each dimension do not necessarily match the reality.

[First embodiment]
A finless heat exchanger 10 according to a first embodiment and a cooling system 1 using the finless heat exchanger 10 will be described with reference to FIGS. 1 to 9.

FIG. 1 is a schematic diagram showing the configuration of a cooling system 1 using a finless heat exchanger 10 according to the present invention. FIG. 2 is a perspective view of the finless heat exchanger 10 according to the first embodiment. FIG. 3 is a side view of the side plate 40 of the finless heat exchanger 10 shown in FIG. 2. FIG. 4 is a schematic front view of the finless heat exchanger 10 shown in FIG. 2. FIG. 5 is a schematic front view of the finless heat exchanger 10 shown in FIG. 4 before the diameter expansion process. FIG. 6 is a side view of the refrigerant tubes 20 of the finless heat exchanger 10 shown in FIG. (A) is a three-dimensional diagram, and (B) is a diagram diagram. FIG. 7 is an enlarged view of the long holes 41 in the side plate 40 of the finless heat exchanger 10 shown in FIG. 3. FIG. 8 is an enlarged view of essential parts of the finless heat exchanger 10 shown in FIG. 5. (A) is a perspective view of the bent pipe part 21 of the refrigerant tube 20 that has been press-processed, and (B) is a perspective view of the bent pipe part 21 shown in (A) inserted into the long hole 41 of the side plate 40. FIG. FIG. 9 is a diagram showing the size relationship between the curved pipe portion 21 of the pressed refrigerant tube 20 and the elongated hole 41 of the side plate 40. As shown in FIG. (A) shows the elongated hole 41 on the left side and the pressed bent pipe part 21 of the refrigerant tube 20 on the right side, and (B) shows the bent pipe part 21 shown in (A) with the long hole 41 on the side plate 40. A state inserted into the hole 41 is shown.

The cooling system 1 is used, for example, in the field of industrial equipment, such as a cooler for a control panel or an oil cooler. As shown in FIG. 1, the cooling system 1 includes, for example, a compressor 3, a condenser 4, a pressure reducing device 5, an evaporator 6, a blower 8 that blows air to the condenser 4, and a blower 8 that blows air to the evaporator 6. A blower 8 is provided. As the condenser 4 and/or the evaporator 6, a finless heat exchanger 10, which will be described later, is used.

In the cooling system 1, the refrigerant compressed by the compressor 3 is supplied to the condenser 4. In the condenser 4, heat exchange is performed between air and refrigerant. As a result, the refrigerant is condensed in the condenser 4. The refrigerant flowing out of the condenser 4 is supplied to a pressure reducing device 5. In the pressure reducing device 5, the pressure of the refrigerant is reduced. The refrigerant flowing out from the pressure reducing device 5 is supplied to the evaporator 6. In the evaporator 6, heat exchange is performed between the air and the refrigerant. As a result, the refrigerant evaporates in the evaporator 6. Thereafter, the refrigerant returns from the evaporator 6 to the compressor 3. The control panel is provided with a finless heat exchanger 10 that functions as an evaporator 6 and a blower 8.

As shown in FIG. 2, the finless heat exchanger 10 includes a refrigerant tube 20 through which the refrigerant flows, a pair of

side plates

40, 40 that fixedly hold the refrigerant tube 20, and a connecting plate that connects the pair of

side plates

40, 40. 60.

The refrigerant tube 20 has a circular tube shape and includes a U-shaped curved tube section 21 and a straight tube section 31 connected to both ends of the curved tube section 21 . The refrigerant tube 20 extends in a meandering manner in multiple stages by a plurality of curved pipe sections 21 and a plurality of straight pipe sections 31. The refrigerant tube 20 has tube ends 12 , 12 at both ends thereof, one tube end 12 being connected to the conduit of the cooling system 1 and the other tube end 12 being connected to the communication part 14 . The refrigerant tube 20 is connected to another refrigerant tube 20 via the communication portion 14 . This allows the plurality of refrigerant tubes 20 to communicate with each other.

The refrigerant tube 20 is made of a metal material with high thermal conductivity, for example, a pure aluminum alloy (1000 series). This makes it possible to achieve lower costs and lighter weight than when using copper, which is expensive and has a large specific gravity. Further, the refrigerant tube 20 has a shape (for example, 6 mm in diameter and 0.6 mm in wall thickness) that can be deformed by a diameter expansion process described below.

As shown in FIG. 3, the side plate 40 has a large number of elongated holes 41 and a plurality of extraction holes 51. A large number of long holes 41 are arranged in a matrix in the vertical and horizontal directions of FIG. The elongated hole 41 is a through hole configured so that a predetermined portion of the curved pipe portion 21 of the refrigerant tube 20 deformed by pressing can be inserted therethrough. The elongated hole 41 in the first embodiment has a shape shown in FIG. 7, and details regarding the shape of the elongated hole 41 will be described later. The extraction hole 51 is a through hole having a size that allows the tube end 12 of the straight pipe portion 31 of the refrigerant tube 20 to be inserted therethrough.

The side plate 40 is made of a metal material with high thermal conductivity, for example, a pure aluminum alloy (1000 series). This makes it possible to achieve lower costs and lighter weight than when using copper, which is expensive and has a large specific gravity. Further, the side plate 40 has a thickness that can ensure a predetermined strength. Note that the side plate 40 can also be made of an aluminum alloy (such as an Al-Mg alloy or an Al-Si alloy) having a composition different from that of the refrigerant tube 20.

FIG. 4 is a schematic front view of a portion of the finless heat exchanger 10 shown in FIG. 2, after the diameter expansion process. In FIG. 4, a pair of

side plates

40, 40 are spaced apart in the left-right direction. The straight pipe portion 31 of the refrigerant tube 20 extends in the left-right direction. The curved tube portion 21 of the refrigerant tube 20 is curved in a U-shape so as to connect two adjacent

straight tube portions

31, 31. The bent pipe portion 21 before the diameter expansion process has a deformed portion that is crushed and deformed by the pressing process, and the deformed portion is inserted into the long hole 41 of the side plate 40 . On the other hand, in the curved tube section 21 after the diameter expansion process, the outer part located outside the side plate 40 is expanded by applying hydraulic pressure to the refrigerant tube 20, so that the outside size of the straight tube section 31 is increased. bulges out to have a size approaching . As a result, the curved tube portion 21 closely contacts the elongated hole 41 and the curved tube portion 21 expands, so that the refrigerant tube 20 is fixed to the side plate 40 .

The relationship between the bent pipe portion 21 and the long hole 41 before the diameter expansion process will be described with reference to FIGS. 5 to 9.

As shown in FIGS. 5, 6, and 8(A), the curved tube section 21 has a pair of curved tube ends 23, 23, a main deformation section 27, and a pair of

sub-deformation sections

25, 25. . The bent pipe end portion 23 is an end located on the straight pipe portion 31 side. The bent tube end portion 23 has approximately the same external size as the straight tube portion 31 and is slightly curved toward the main deformation portion 27 side.

The main deformation portion 27 has an arcuate shape. The main deformation portion 27 has a flat portion 28 formed by pressing. The thickness of the flat part 28 is, for example, 20% to 73%, preferably 45% to 72%, of the thickness before deformation by pressing (approximately the same external size as the straight pipe part 31), Preferably it is 68% to 71%. The arc angle of the flat portion 28 is, for example, 70 degrees to 110 degrees, preferably 80 degrees to 100 degrees, and preferably 85 degrees to 95 degrees, when viewed from the front.

The secondary deformation section 25 is located between the bent tube end 23 and the main deformation section 27. The secondary deformation portion 25 has a curved shape that is secondary deformed due to the formation of the flat portion 28 . In other words, the curved shape of the sub-deformable portion 25 has a shape that connects the curved pipe end portion 23 and the flat portion 28 of the main deformable portion 27 .

As shown in FIG. 7, the long hole 41 of the side plate 40 has a central opening 47 and a pair of

end openings

43, 43.

The central opening 47 is configured to receive the main deformation section 27. The central opening 47 has a rectangular shape defined by a pair of

long sides

48, 48 that are spaced from each other and opposed to each other. The long side 48 extends in the longitudinal direction (in other words, the vertical direction in FIG. 7, which is the direction in which the straight pipe portions 31 of the refrigerant tubes 20 are arranged).

A pair of

long sides

48, 48 in the central opening 47 shown in FIG. 7 each have a central protrusion 49 at the central portion in the longitudinal direction. The protrusion height (on one side only) of the central protrusion 49 is, for example, 0.05 mm to 1.6 mm, preferably 0.05 mm to 0.8 mm, and preferably 0.05 mm to 0.1 mm. The pair of

central protrusions

49, 49 have a shape that protrudes while curving toward each other. In other words, the central portion of the central opening 47 is narrowed by the pair of curved

central projections

49, 49. Therefore, the central opening 47 shown in FIG. 7 has a curved narrow shape.

The pair of

end openings

43 , 43 are located at both ends of the central opening 47 and are configured to partially receive the sub-deformation portion 25 and the bent pipe end portion 23 . The end opening 43 is an arc defined by a circular arc side 44 extending from an end of one long side 48 of the pair of

long sides

48, 48 to an end of the other long side 48 of the pair of

long sides

48, 48. It has a shape. Specifically, the end opening 43 has a long axis extending along the long side 48, a short axis perpendicular to the long axis, a rounded blunt end located on the side of the border edge 45, and a border. It has an oval shape with a pointed tip located opposite the edge 45. Therefore, the end opening 43 shown in FIG. 7 has an oval shape.

A boundary edge 45 is formed at the boundary between the long side 48 that defines the central opening 47 and the arcuate side 44 that defines the end opening 43. Since the boundary edge 45 is a discontinuous transition from the long side 48 to the arcuate side 44, it has a pointed shape.

The bent pipe portion 21 and the elongated hole 41 configured as described above are set in the manner shown in FIGS. 8(B) and 9 before the diameter expansion process. That is, the rectangular center opening 47 receives the main deformation section 27, and the pair of

arcuate end openings

43, 43 partially receives the sub-deformation section 25 and the curved pipe end 23. The bent pipe portion 21 is inserted into the elongated hole 41. In the inserted state, there is a slight gap between the long side 48 of the central opening 47 and the flat part 28 of the main deformable part 27, while the arcuate side 44 of the end opening 43 It partially abuts against the sub-deformed portion 25 and the bent pipe end portion 23 of. Thereby, the bent pipe portion 21 inserted into the long hole 41 can be easily and accurately positioned with respect to the long hole 41.

With the bent pipe section 21 inserted into the elongated hole 41, hydraulic diameter expansion pressure is applied through the tube end 12 of the refrigerant tube 20. The diameter expansion pressure applied only needs to expand the diameter of the deformed parts (main deformation part 27 and sub-deformation part 25) deformed by pressing in the bent pipe part 21, so it is more effective than when expanding the diameter of the straight pipe part 31. Also, low pressure is sufficient. As the diameter expansion pressure, a pressure before the refrigerant tube 20 bursts is applied, and the diameter expansion pressure is, for example, 70% to 90% of the bursting pressure of the refrigerant tube 20, preferably 75% of the bursting pressure of the refrigerant tube 20. % to 88%, preferably 82% to 87% of the burst pressure of the refrigerant tube 20.

The largely deformed main deformed portion 27 attempts to return to its original shape with a smaller diameter expansion pressure than the slightly deformed auxiliary deformed portion 25. In other words, when a certain diameter expansion pressure is applied, the main deformation part 27 bulges out more easily than the sub-deformation part 25, so the main deformation part 27 is more mechanically fixed than the sub-deformation part 25. Contribute to However, the engagement of the pair of

end openings

43, 43 with the sub-deformable portion 25 and the bent tube end portion 23 contributes to preventing the bent tube portion 21 from moving in the longitudinal direction of the elongated hole 41.

In the curved pipe portion 21 inserted into the elongated hole 41, the outer portion located outside the inner edge of the elongated hole 41 bulges due to the application of diameter expansion pressure. As the diameter expansion pressure increases, the outer portion bulges out to have a size that approaches the straight pipe portion 31. Since the risk of rupturing the refrigerant tube 20 increases as the diameter expansion pressure increases, the diameter expansion pressure within the above-mentioned predetermined pressure range is applied. In addition, the portion of the bent tube portion 21 inserted into the elongated hole 41 that faces the elongated hole 41 is regulated by the elongated hole 41 and engages with the elongated hole 41 during the expansion process of the bent tube portion 21 .

During the expansion process of the curved tube section 21, the main deformation section 27 closely contacts the pair of

long sides

48, 48 of the central opening 47, and the secondary deformation section 25 and the curved tube end 23 close to the pair of end openings. 43, 43 closely contacts a pair of

arcuate sides

44, 44. As a result, the refrigerant tube 20 can be mechanically fixed to the side plate 40 (attached in a fixed state) by the curved tube portion 21 closely contacting the elongated hole 41 and expanding the curved tube portion 21. Therefore, cost reduction and yield improvement can be realized.

Further, during the expansion process of the curved pipe portion 21, the boundary edge 45 having a sharp shape engages with the sub-deformation portion 25 so as to bite into it. Thereby, the degree of mechanical fixation of the refrigerant tube 20 to the side plate 40 is improved.

As described above, the long hole 41 shown in FIG. 7 has a narrow curved central opening 47 and an egg-shaped end opening 43. The narrow curved shape of the central opening 47 shown in FIG. This makes it possible to bite into the portion 28. Thereby, it is possible to reduce the chance of getting caught when inserting the main deformable portion 27 and to improve the degree of locking in the central opening 47.

The arcuate side 44 of the end opening 43 shown in FIG. and a pointed tip located opposite the bounding edge 45. On the obtuse end side, the angle that the arcuate side 44 makes with the long side 48 becomes larger, so the boundary edge 45 becomes sharper. Therefore, during the expansion process of the curved pipe section 21, the contact area of the end opening 43 against the arcuate side 44 becomes larger, and the boundary edge 45 can bite into the sub-deformed section 25 or the end of the curved pipe. . Thereby, the degree of locking in the end opening 43 can be improved.

[Second embodiment]
A finless heat exchanger 10 according to a second embodiment will be described with reference to FIG. 10. FIG. 10 is an enlarged view of the long holes 41 in the side plate 40 of the finless heat exchanger 10 according to the second embodiment.

The finless heat exchanger 10 according to the second embodiment is different from the first embodiment only in the shape of the long holes 41, and the other configurations are the same as the first embodiment. Therefore, the explanation will focus on the differences from the first embodiment.

The elongated hole 41 shown in FIG. 10 has a central opening 47 with an evenly spaced shape and a pair of long sides 48 extending in parallel, and an end opening 43 with a perfect circular shape. The equally spaced shape of the central opening 47 shown in FIG. becomes easier. Thereby, smooth insertion of the main deformable portion 27 and cost reduction can be realized.

The arcuate side 44 of the end opening 43 shown in FIG. 10 is a portion of a perfect circle having a radius of curvature slightly smaller than the outer diameter of the straight pipe portion 31. Furthermore, since the boundary edge 45 is a discontinuous transition point from the long side 48 to the arcuate side 44 having a small radius of curvature, it has a shape that is more pointed than the oval-shaped arcuate side 44 described in the first embodiment. . Therefore, the end opening 43 can be easily processed, and the boundary edge 45 can bite into the sub-deformed portion 25 or the end of the curved pipe. This makes it possible to reduce costs and improve the degree of locking.

[Third embodiment]
A finless heat exchanger 10 according to a third embodiment will be described with reference to FIG. 11. FIG. 11 is an enlarged view of the long holes 41 in the side plate 40 of the finless heat exchanger 10 according to the third embodiment.

The finless heat exchanger 10 according to the third embodiment is different from the first embodiment only in the shape of the long holes 41, and the other configurations are the same as the first embodiment. Therefore, the explanation will focus on the differences from the first embodiment.

The elongated hole 41 shown in FIG. 11 has a central opening 47 with an evenly spaced shape in which a pair of

long sides

48, 48 extend in parallel, and an end opening 43 with an elliptical shape. The equally spaced shape of the central opening 47 shown in FIG. 11 allows the flat part 28 to be held from the short side direction of the elongated hole 41 during the expansion process of the curved tube part 21, and also makes it possible to easily process the central opening 47. becomes easier. Thereby, smooth insertion of the main deformable portion 27 and cost reduction can be realized.

The arcuate side 44 of the end opening 43 shown in FIG. 11 is a part of an ellipse whose long axis extends along the long side 48 and whose short axis is slightly smaller than the outer diameter of the straight pipe portion 31. Further, the boundary edge 45 has a shape that is less sharp than the oval arcuate side 44 described in the first embodiment. Therefore, during the expansion process of the curved pipe portion 21, the contact area of the end opening 43 against the arcuate side 44 becomes larger, and the boundary edge 45 can gently bite into the sub-deformed portion 25 or the curved pipe end. Make it. Thereby, it is possible to improve the degree of locking in the end opening 43 and reduce damage caused by biting.

[Fourth embodiment]
A finless heat exchanger 10 according to a fourth embodiment will be described with reference to FIG. 12. FIG. 12 is an enlarged view of the long holes 41 in the side plate 40 of the finless heat exchanger 10 according to the fourth embodiment.

The finless heat exchanger 10 according to the fourth embodiment is different from the first embodiment only in the shape of the long holes 41, and the other configurations are the same as the first embodiment. Therefore, the explanation will focus on the differences from the first embodiment.

The elongated hole 41 shown in FIG. 12 has a central opening 47 with an evenly spaced shape in which a pair of

long sides

48, 48 extend in parallel, and an egg-shaped end opening 43. The equally spaced shape of the central opening 47 shown in FIG. 12 makes it possible to hold the flat part 28 from the short side direction of the elongated hole 41 during the expansion process of the curved tube part 21, and also makes it possible to process the central opening 47. becomes easier. Thereby, smooth insertion of the main deformable portion 27 and cost reduction can be realized.

The arcuate side 44 in the end opening 43 shown in FIG. 12 is a part of the same oval shape as described in the first embodiment. Therefore, as in the first embodiment, during the expansion process of the curved pipe portion 21, the contact area of the end opening 43 with the arcuate side 44 becomes larger, and the boundary edge 45 is It allows you to dig into the parts. Thereby, the degree of locking in the end opening 43 can be improved.

[Fifth embodiment]
A finless heat exchanger 10 according to a fifth embodiment will be described with reference to FIG. 13. FIG. 13 is an enlarged view of the long holes 41 in the side plate 40 of the finless heat exchanger 10 according to the fifth embodiment.

The finless heat exchanger 10 according to the fifth embodiment differs from the first embodiment only in the shape of the long holes 41, and the other configurations are the same as the first embodiment. Therefore, the explanation will focus on the differences from the first embodiment.

The elongated hole 41 shown in FIG. 13 has a central opening 47 with a narrow inclined width from which central protrusions 49 of a pair of

long sides

48 and 48 protrude at an inclined angle, and an end opening 43 with a perfect circular shape. The inclination angle is, for example, 0.5 degrees to 3 degrees, preferably 0.5 degrees to 2 degrees, and preferably 0.5 degrees to 1 degree. The inclined narrow width shape of the central opening 47 shown in FIG. This allows the protruding portion 49 to strongly bite into the flat portion 28. Thereby, the degree of locking in the central opening 47 can be further improved.

The arcuate side 44 of the end opening 43 shown in FIG. 13 is a part of a perfect circle having a radius of curvature slightly smaller than the outer diameter of the straight pipe portion 31. Furthermore, since the boundary edge 45 is a discontinuous transition point from the long side 48 to the arcuate side 44 having a small radius of curvature, it has a shape that is more pointed than the oval-shaped arcuate side 44 described in the first embodiment. . Therefore, the end opening 43 can be easily processed, and the boundary edge 45 can bite into the sub-deformed portion 25 or the end of the curved pipe. This makes it possible to reduce costs and improve the degree of locking in the end opening 43.

[Sixth embodiment]
A finless heat exchanger 10 according to a sixth embodiment will be described with reference to FIG. 14. FIG. 14 is an enlarged view of the long holes 41 in the side plate 40 of the finless heat exchanger 10 according to the sixth embodiment.

The finless heat exchanger 10 according to the sixth embodiment is different from the first embodiment only in the shape of the long holes 41, and the other configurations are the same as the first embodiment. Therefore, the explanation will focus on the differences from the first embodiment.

The elongated hole 41 shown in FIG. 14 has a narrow curved central opening 47 in which central protrusions 49 of a pair of

long sides

48, 48 protrude while being curved, and an end opening 43 in a perfect circular shape. The curved narrow shape of the central opening 47 shown in FIG. 14 has the same shape as described in the first embodiment. Therefore, similarly to the first embodiment, during the expansion process of the curved pipe portion 21, the flat portion 28 is held from the lateral direction of the elongated hole 41, and the curved central protrusion 49 bites into the flat portion 28. make it possible. Thereby, it is possible to reduce the chance of getting caught when inserting the main deformable portion 27 and to improve the degree of locking in the central opening 47.

The arcuate side 44 of the end opening 43 shown in FIG. 14 is a portion of a perfect circle having a radius of curvature slightly smaller than the outer diameter of the straight pipe portion 31. Furthermore, since the boundary edge 45 is a discontinuous transition point from the long side 48 to the arcuate side 44 having a small radius of curvature, it has a shape that is more pointed than the oval-shaped arcuate side 44 described in the first embodiment. . Therefore, the end opening 43 can be easily processed, and the boundary edge 45 can bite into the sub-deformed portion 25 or the end of the curved pipe. This makes it possible to reduce costs and improve the degree of locking in the end opening 43.

Although specific embodiments of this invention have been described, this invention is not limited to the above embodiments, and can be implemented with various changes within the scope of this invention.

In the elongated holes 41 of the side plate 40, the central openings 47 may have an equally spaced shape, a curved narrow width shape, or an inclined narrow width shape, and the end openings 43 may have a perfect circular shape, an elliptical shape, or an oval shape, depending on the required specifications. They can be selected and combined as appropriate. In addition to the embodiments described above, the central opening 47 has a narrow curved width and the end openings 43 have an elliptical shape, and the central opening 47 has a narrow sloped width and the end openings 43 have an elliptical shape. Alternatively, the central opening 47 may have an inclined narrow shape and the end openings 43 may have an oval shape.

In the above embodiment, a pure aluminum-based alloy is illustrated as the refrigerant tube 20, but copper can also be used.

The present invention and embodiments can be summarized as follows.

The finless heat exchanger 10 according to the first aspect of the invention includes:
A refrigerant tube 20 extending in a meandering manner and having a U-shaped curved tube section 21 and straight tube sections 31 connected to both ends of the curved tube section 21;
A side plate 40 having a long hole 41,
The bent pipe portion 21 includes a bent pipe end portion 23 located on the side of the straight pipe portion 31, a main deformation portion 27 curved in an arc shape, and a portion between the bent pipe end portion 23 and the main deformation portion 27. and a sub-deformation portion 25 located therein.
The main deformation part 27 has a flat part 28 formed by pressing,
The secondary deformation portion 25 has a curved shape secondary to deformation due to the formation of the flat portion 28,
The elongated hole 41 has a central opening 47 that receives the main deformable portion 27, and a pair of end openings 43 that are located at both ends of the central opening 47 and partially receive the secondary deformable portion 25 and the bent pipe end portion 23. , 43,
By expanding the diameter of the curved tube portion 21 with the curved tube portion 21 inserted into the long hole 41 and bringing the curved tube portion 21 into close contact with the long hole 41, the refrigerant tube 20 is It is characterized in that it is fixed to the side plate 40.

According to the above aspect, the refrigerant tube 20 can be mechanically fixed to the side plate 40 by the curved tube portion 21 closely contacting the elongated hole 41 and the curved tube portion 21 expanding, thereby reducing costs. It is possible to realize improvements in production and yield.

Furthermore, the finless heat exchanger 10 according to the second aspect has the following features in the first aspect:
The central opening 47 has a rectangular shape defined by a pair of

long sides

48, 48 that are spaced apart from each other, and the end opening 43 is located at the end of one long side 48 of the pair of

long sides

48, 48. It has an arcuate shape defined by an arcuate side 44 extending from the end of the pair of long sides 48 to the end of the other long side 48 of the pair of

long sides

48, 48.

According to the above aspect, the bent pipe portion 21 inserted into the long hole 41 can be easily and accurately positioned with respect to the long hole 41.

Furthermore, the finless heat exchanger 10 according to the third aspect has the following features in the second aspect:
The central opening 47 has a shape in which the pair of

long sides

48, 48 extend in parallel at equal intervals, a curved narrow shape in which the central protrusion 49 of the pair of

long sides

48, 48 protrudes while being curved, or, The central protruding portion 49 of the pair of

long sides

48, 48 has an inclined narrow shape that protrudes at an inclined angle.

According to the above aspect, the equally spaced shape makes it possible to smoothly insert the main deformable portion 27 and reduce costs, and the narrow curved shape reduces the possibility of getting caught during insertion, and The degree of locking can be improved, and the narrow slope shape can further improve the degree of locking at the central opening 47.

Furthermore, the finless heat exchanger 10 according to the fourth aspect has the following features in the second or third aspect:
The end opening 43 has a perfect circular shape, an elliptical shape, or an oval shape.

According to the above aspect, the perfect circular shape can reduce costs and improve the degree of locking at the end opening 43, and the elliptical shape can improve the degree of locking at the end opening 43 and reduce damage caused by locking. The oval shape can improve the degree of locking at the end opening 43.

Furthermore, the finless heat exchanger 10 according to the fifth aspect has the following features in the first aspect:
The central opening 47 has a narrow curved shape in which the central protrusion 49 of the pair of

long sides

48 and 48 protrudes while being curved, and the end opening 43 has an oval shape.

According to the above aspect, the curved and narrow shape of the central opening 47 reduces the possibility of getting caught during insertion and improves the degree of locking in the central opening 47, and the oval shape of the end opening 43 allows the end The degree of locking in the opening 43 can be improved.

Furthermore, the finless heat exchanger 10 according to the sixth aspect has the following features in any of the first to fifth aspects:
The refrigerant tube 20 and the side plate 40 are made of aluminum alloy.

According to the above aspect, cost reduction and weight reduction can be achieved.

Furthermore, the cooling system 1 according to the seventh aspect includes:
A compressor, a condenser, a pressure reducing device, an evaporator, and a blower that provides forced ventilation to the condenser or the evaporator,
The condenser or the evaporator is the finless heat exchanger according to any one of the first to fifth aspects.

1... Cooling system 3... Compressor 4... Condenser 5... Pressure reducing device 6... Evaporator 8... Air blower 10... Finless heat exchanger 12... Tube end 14... Communication part 20... Refrigerant tube 21... Bent pipe part 23... Bent pipe End portion 25... Secondary deformation portion 27... Main deformation portion 28... Flat portion 31... Straight pipe portion 40... Side plate 41... Long hole 43... End opening 44... Arc side 45... Boundary edge 47... Center opening 48... Long side 49... Central protrusion 51...Ejection hole 60...Connection plate

Claims

A refrigerant tube extending in a meandering manner and having a U-shaped curved tube portion and a straight tube portion connected to both ends of the curved tube portion;
Equipped with a side plate having long holes,
The bent pipe portion includes a bent pipe end portion located on the side of the straight pipe portion, a main deformation portion curved in an arc shape, and a secondary deformation portion located between the bent pipe end portion and the main deformation portion. has
The main deformation part has a flat part formed by pressing,
The secondary deformation portion has a curved shape secondary to deformation due to the formation of the flat portion,
The elongated hole has a central opening that receives the main deformation part, and a pair of end openings that are located at both ends of the central opening and partially receive the secondary deformation part and the bent pipe end,
The refrigerant tube is fixed to the side plate by expanding the diameter of the curved tube portion with the curved tube portion inserted into the long hole and bringing the curved tube portion into close contact with the long hole. A finless heat exchanger characterized by:
The central opening has a rectangular shape defined by a pair of spaced and opposing long sides, and the end opening extends from the end of one of the pair of long sides to the other of the pair of long sides. The finless heat exchanger according to claim 1, characterized in that the finless heat exchanger has an arcuate shape defined by an arcuate side extending to an end of a long side of the finless heat exchanger.
The central opening may have an evenly spaced shape in which the pair of long sides extend in parallel, a curved narrow shape in which the central protrusion of the pair of long sides protrudes while being curved, or a central opening in the pair of long sides. The finless heat exchanger according to claim 2, wherein the finless heat exchanger has an inclined narrow shape in which the portion protrudes at an inclined angle.
The finless heat exchanger according to claim 2 or 3, wherein the end opening has a perfect circular shape, an elliptical shape, or an oval shape.
2. The central opening has a narrow curved shape in which central protrusions on the pair of long sides protrude while being curved, and the end openings have an oval shape. Finless heat exchanger.
The finless heat exchanger according to any one of claims 1 to 5, wherein the refrigerant tube and the side plate are made of an aluminum alloy.
A compressor, a condenser, a pressure reducing device, an evaporator, and a blower that provides forced ventilation to the condenser or the evaporator,
A cooling system, wherein the condenser or the evaporator is a finless heat exchanger according to any one of claims 1 to 6.